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 * Copyright (c) 2012, Google Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#ifndef SKY_ENGINE_PLATFORM_GRAPHICS_REGIONTRACKER_H_
#define SKY_ENGINE_PLATFORM_GRAPHICS_REGIONTRACKER_H_

#include "flutter/sky/engine/platform/PlatformExport.h"
#include "flutter/sky/engine/platform/geometry/IntRect.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "third_party/skia/include/core/SkPaint.h"
#include "third_party/skia/include/core/SkPoint.h"
#include "third_party/skia/include/core/SkRect.h"

namespace blink {
class GraphicsContext;

enum RegionTrackingMode { TrackOpaqueRegion, TRackOverwriteRegion };

// This class is an encapsulation of functionality for GraphicsContext, and its
// methods are mirrored there for the outside world. It tracks paints and
// computes what area will be opaque.
class PLATFORM_EXPORT RegionTracker final {
 public:
  RegionTracker();

  // The resulting opaque region as a single rect.
  IntRect asRect() const;

  void pushCanvasLayer(const SkPaint*);
  void popCanvasLayer(const GraphicsContext*);

  void setImageMask(const SkRect& imageOpaqueRect);

  enum RegionType { Opaque, Overwrite };

  // Set this to true to track regions that occlude the destination instead of
  // only regions that produce opaque pixels.
  void setTrackedRegionType(RegionType type) { m_trackedRegionType = type; }

  enum DrawType { FillOnly, FillOrStroke };

  void didDrawRect(const GraphicsContext*,
                   const SkRect&,
                   const SkPaint&,
                   const SkBitmap* sourceBitmap);
  void didDrawPath(const GraphicsContext*, const SkPath&, const SkPaint&);
  void didDrawPoints(const GraphicsContext*,
                     SkCanvas::PointMode,
                     int numPoints,
                     const SkPoint[],
                     const SkPaint&);
  void didDrawBounded(const GraphicsContext*, const SkRect&, const SkPaint&);
  void didDrawUnbounded(const GraphicsContext*, const SkPaint&, DrawType);

  struct CanvasLayerState {
    CanvasLayerState() : hasImageMask(false), opaqueRect(SkRect::MakeEmpty()) {}

    SkPaint paint;

    // An image mask is being applied to the layer.
    bool hasImageMask;
    // The opaque area in the image mask.
    SkRect imageOpaqueRect;

    SkRect opaqueRect;
  };

  void reset();

 private:
  void didDraw(const GraphicsContext*,
               const SkRect&,
               const SkPaint&,
               const SkBitmap* sourceBitmap,
               bool fillsBounds,
               DrawType);
  void applyOpaqueRegionFromLayer(const GraphicsContext*,
                                  const SkRect& layerOpaqueRect,
                                  const SkPaint&);
  void markRectAsOpaque(const SkRect&);
  void markRectAsNonOpaque(const SkRect&);
  void markAllAsNonOpaque();

  SkRect& currentTrackingOpaqueRect();

  SkRect m_opaqueRect;
  RegionType m_trackedRegionType;

  Vector<CanvasLayerState, 3> m_canvasLayerStack;
};

}  // namespace blink

#endif  // SKY_ENGINE_PLATFORM_GRAPHICS_REGIONTRACKER_H_
